Harappa was an Indus Valley urban center. It lies in Punjab Province, Pakistan, on an old bed of the River Ravi. The latest research has revealed at least five mounds at Harappa that 3-D renditions of Harappa show to have been surrounded by extensive walls. Two have large walls around them, perhaps as much for trade regulation as defense. A structure once considered a granary is now thought to have been a palace with ventilated air ducts. An abundance of terracotta figurines Harappa provided the first clues in the 19th century to the ancient Indus Valley - often abbreviated as Harappan - civilization.

Mohenjodaro is probably the best known Indus Valley site. Mohenjo-Daro is in Sindh, Pakistan, next to the Indus River, not far from the very early human flint mining quarries at Rohri. The Indus once flowed far close to Mohenjo-daro than it does today. Here the Great Bath, uniform buildings and weights, hidden drains and other hallmarks of the civilization were discovered in the 1920's. This is where the most unicorn seals have been found. Due to a rising water table, most of the site remains unexcavated, and its earliest levels have not been reached.

Dholavira is located on Khadir Beit, an island in the Great Rann of Kutch in Gujarat State, India. It has only been excavated since 1990. As large as Harappa and Mohenjodaro, it has some of the best preserved architecture. A tantalizing signboard with Indus script has also been discovered. Dholavira appears to have had five Great Baths, at least one even larger than the one in Mohenjodaro, but whether they are all from the Indus period remains to be seen.

Lothal is on the top of the Gulf of Cambay in Gujarat, India, near the Sabarmati River and the Arabian Sea. It is the most extensively researched Harappan coastal site. A bead factory and Mesopotamian seal have been found here suggesting that like many sites on the Gulf of Cambay, it was deeply into training.

Rakhigarhi is a recently discovered, still unexcavated city in Haryana, India. It is as large as Harappa, Mohenjodaro and Ganweriwala.

Gola Dhoro is a very recently - 2004 - excavated site in Gujarat, India. A completely unique ancient Indus seal was found there, as well as extensive evidence for the sudden evacuation of this tiny town with very concentrated manufacturing facilities.
Rakhigarhi is a recently discovered, still unexcavated city in Haryana, India. It is as large as Harappa, Mohenjodaro and Ganweriwala.

Ganeriwala is in Punjab, Pakistan near the Indian border. It was discovered in the 1970's, and at 80 hectares is as large as Mohenjodaro. It is near a dry bed of the former Ghaggar or Sarasvati River, and has not been excavated, yet. Equidistant between Harappa and Mohenjodaro, Ganweriwala may have been the urban center of a third Indus Valley region covering copper-rich Rajasthan.

Daimabad is in Maharashtra near Bombay. Discovered in 1958, it is a controversial site. Some suggest that the pottery and single shard with Indus Valley signs on it is definitive of Harappan settlement; others say the evidence is not enough. A unique hoard of exquisite bronze chariots and animals that may or may not be of Indus Valley style was also found here.

Chanudarho is 80 miles south of Mohenjodaro in Sindh. It was a manufacturing center. Various tool, shell, bone and seal-making facilities which involved writing were found. Beads were made using efficiently layered floors. Chanudarho seems also to have been hastily abandoned.

Sutkagen Dor in Baluchistan next to Iran is the westernmost known Harappan site. It is thought to have once been on a navigable inlet of the Arabian Sea. The usual citadel and town are present, as well as defensive walls 30 feet wide. Sutkagen Dor would have been on the trade route from Lothal in Gujarat to Mesopotamia and was probably heavily involved in the fishing trade that exists today in the coast along Baluchistan.

All these sites flourished for various periods between 3500 and 1700 B.C. although now dry riverbeds elsewhere in the subcontinent, if not earlier. There are probably many more important Indus Valley sites. Some must have been lost or destroyed by shifting river paths. Others are probably buried under modern towns.

What does seem clear is that the important sites were commercial centers. They are on rivers or near the coast. Various specialized manufacturing facilities suggest that they were heavily involved in trade with each other and far outside the region.